Bangle.js 2

Bangle.js is the successor to Bangle.js, and is based on the SMA Q3.

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Bangle.js 2 is an open, hackable smartwatch

You can easily install new apps from the web or develop your own using JavaScript or a graphical programming language (Blockly). All you need is a Web Browser (Chrome, Edge or Opera) and you can upload apps or write code to run on your watch wirelessly! Bangle.js is water resistant, AI enabled, and comes with Bluetooth Low Energy, GPS, a heart rate monitor, accelerometer and more.

Contents

Features

Quick Usage Notes

Check out the Bangle.js 2 Getting Started Guide

There are a few things to know that'll help you get started quickly:

This video shows you how to get started using the menu and App Loader:

Please check out The Bangle.js Wiki for more hints and common questions.

Contact Corrosion / Skin Irritation

Bangle.js 2 has 4 contacts on the rear. The two on the ends are used for charging and are not powered, however the middle two are SWD debug/programming pins connected straight to the CPU. One has a weak resistor connecting it to 3.3v. At most, 0.0001A of current at 3.3v can be provided, however if exposed to salty water (eg sweat) or other conductive conditions, the contacts will corrode and it is possible that in extreme cases there could be some skin irritation.

Bangle.js 2 devices sold since the KickStarter campaign ship with a small piece of tape covering the contacts to prevent any problems. If you have a watch without this tape we would strongly advise you apply some paint, tape, a sticker or laquer over the middle two contacts as shown in the images below:

Charging

The supplied charge cable connects to a USB port to charge Bangle.js (despite there being 4 wires, those are for SWD programming and there is no USB data connection).

Do not force the cable on to your Bangle.js If the cable does not pull itself on to the Bangle it's probably the wrong way around. Forcing it to make contact in this case could damage your Bangle.

The cable is magnetic and the wires are connected to USB power. While the cable in Bangle.js 2 does have short circuit protection, please do not leave your cable plugged in or it might attract itself to the nearest magnetic (probably conductive) object and short out.

DO NOT CONNECT A BANGLE.JS 1 CHARGE CABLE TO BANGLE.JS 2 - there are a different number of pins and connecting it could cause damage to your device.

We'll be selling new/replacement Bangle.js charge cables on shop.espruino.com soon, however until then (or if you need a cable next day) you can use:

Apps

Apps are provided by the same Bangle.js app loader as for Bangle.js 1, you just need to select Bangle.js 2 when prompted (or from the drop-down in the top left).

For iPhone users, web bluetooth is not supported by default with Safari. You will need a browser that has support for web bluetooth such as WebBLE. If your Bangle is paired for notifications, you will need to disconnect from the device for it to show up when you press the "Connect" button. This is due to an issue with the WebBLE browser, and there is an open issue for it.

Powering off

Resetting

If you release the button too late you'll enter bootloader mode, in which case you need to wait for 30 seconds for the watch to automatically exit.

Recovery menu

On 2v19 firmware and later, if something has gone wrong you can enter a Recovery menu:

Resetting without loading any code

If you uploaded some code that runs at startup and breaks Bangle.js you may need to do this.

2v19 firmware

Start the Recovery menu (see above) by holding the button at boot time, then choose Clean Boot

pre-2v19 firmware

It won’t delete anything, so unless you fix/remove the broken code (see "Deleting all Code") Bangle.js will remain broken next time it restarts.

Deleting all code

You can do this either while your watch is in its normal state, or if you have reset it without loading any code (above).

2v19 firmware

Start the Recovery menu (see above) by holding the button at boot time, then choose Factory Reset

pre-2v19 firmware

Either

This will erase everything and install just the default apps.

Or

Deleting apps

Tutorials

In general, most tutorials related to Bangle.js 1 should work on Bangle.js 2, as long as you're aware that you only have one button and the screen resolution is different - see below under Information.

Upon release, specific Bangle.js 2 tutorials will be added here.

Tutorials using Bangle.js:

Bangle.js DevelopmentBangle.js Development Bangle.js Getting StartedBangle.js Getting Started Testing Espruino on Bangle.js 2Testing Espruino on Bangle.js 2 Bangle.js First Application (Timer)Bangle.js First Application (Timer) Bangle.js Clock FacesBangle.js Clock Faces Adding an app to the Bangle.js App LoaderAdding an app to the Bangle.js App Loader Gadgetbridge for AndroidGadgetbridge for Android Bangle.js Technical InformationBangle.js Technical Information Bangle.js InternationalisationBangle.js Internationalisation Bangle.js Clock InfoBangle.js Clock Info Bangle.js Fast LoadingBangle.js Fast Loading BTHome and Home Assistant SetupBTHome and Home Assistant Setup Adding a Bangle.js App Settings PageAdding a Bangle.js App Settings Page Bangle.js 2 DisassemblyBangle.js 2 Disassembly Bangle.js 2 Technical InformationBangle.js 2 Technical Information Bangle.js App CustomiserBangle.js App Customiser Stopping Bangle.js Reset by ButtonStopping Bangle.js Reset by Button Bangle.js Layout libraryBangle.js Layout library Bangle.js Hideable WidgetsBangle.js Hideable Widgets Controlling Espruino from Tensorflow on the DesktopControlling Espruino from Tensorflow on the Desktop Bookmarklets with Web BluetoothBookmarklets with Web Bluetooth Adding a Custom Boot ScreenAdding a Custom Boot Screen Bangle.js Data StreamingBangle.js Data Streaming Bangle.js WidgetsBangle.js Widgets Bangle.js and Edge Impulse for Machine LearningBangle.js and Edge Impulse for Machine Learning Bangle.js Code GuidelinesBangle.js Code Guidelines Bangle.js Data StorageBangle.js Data Storage Bangle.js Software ModificationBangle.js Software Modification Bangle.js App Loader CustomisationBangle.js App Loader Customisation Bangle.js Clock Face FontsBangle.js Clock Face Fonts Pixl.js and Bangle.js MenusPixl.js and Bangle.js Menus Bangle.js GraphicsBangle.js Graphics Bangle.js Strap ModificationsBangle.js Strap Modifications Bangle.js DisassemblyBangle.js Disassembly Puck.js Control from Android using DroidScriptPuck.js Control from Android using DroidScript

Tutorials using Bluetooth LE:

BLE Advertising with Node.js/Python/C#/AndroidBLE Advertising with Node.js/Python/C#/Android Quick Start (Bluetooth LE)Quick Start (Bluetooth LE) Automatic Data DownloadAutomatic Data Download BTHome LibraryBTHome Library Puck.js to GCP BigQuery & Data StudioPuck.js to GCP BigQuery & Data Studio Stream from Puck.js to AWS IOT Core & SNS EmailStream from Puck.js to AWS IOT Core & SNS Email Bluetooth LE UARTs (NUS)Bluetooth LE UARTs (NUS) Bluetooth LE HID KeyboardsBluetooth LE HID Keyboards Bluetooth LE Security and Access ControlBluetooth LE Security and Access Control Bluetooth LE MIDIBluetooth LE MIDI Web Bluetooth on LinuxWeb Bluetooth on Linux Bluetooth Time SetterBluetooth Time Setter Using Web Bluetooth with EspruinoUsing Web Bluetooth with Espruino Battery MonitorBattery Monitor Bluetooth LE and If This Then ThatBluetooth LE and If This Then That Tilt Hydrometer RepeaterTilt Hydrometer Repeater UART.js LibraryUART.js Library iBeaconsiBeacons Eddystone BeaconsEddystone Beacons Bluetooth LE PrintersBluetooth LE Printers Bluetooth LE and Node-RED with MQTTBluetooth LE and Node-RED with MQTT Bluetooth Music ControllerBluetooth Music Controller Controlling Bluetooth Lights with Puck.jsControlling Bluetooth Lights with Puck.js Bluetooth LE HTTP ProxiesBluetooth LE HTTP Proxies Exercise Machine controlled VideoExercise Machine controlled Video BLE CommunicationsBLE Communications About Bluetooth LE (BLE)About Bluetooth LE (BLE) Puck.js with SMS controlPuck.js with SMS control Pixl.js SMS Remote MonitoringPixl.js SMS Remote Monitoring Web IDE on a Raspberry PiWeb IDE on a Raspberry Pi Puck.js Bluetooth with the Graphical EditorPuck.js Bluetooth with the Graphical Editor Controlling Other BLE Espruino DevicesControlling Other BLE Espruino Devices Pixl.js Simple LoggerPixl.js Simple Logger Pixl.js Multiplayer Pong GamePixl.js Multiplayer Pong Game Pixl.js Bluetooth to Ethernet MQTT BridgePixl.js Bluetooth to Ethernet MQTT Bridge Bluefruit LE app interfaceBluefruit LE app interface

Tutorials using Bluetooth LE and functionality that may not be part of Bangle.js:

BTHome Door Sensor for Home AssistantBTHome Door Sensor for Home Assistant Pixl.js Wireless Temperature DisplayPixl.js Wireless Temperature Display Turning an Espruino Puck.js Into a Universal Presentation ClickerTurning an Espruino Puck.js Into a Universal Presentation Clicker Interfacing to a PCInterfacing to a PC DIY Smart MeterDIY Smart Meter LEGO Power Functions Clone Remote Control (Mould King M-0006 / Kaiyu / Bandra / AKOGD / MayD / etc)LEGO Power Functions Clone Remote Control (Mould King M-0006 / Kaiyu / Bandra / AKOGD / MayD / etc) Puckmote - Universal Remote ControlPuckmote - Universal Remote Control IoT for Kitchen GardensIoT for Kitchen Gardens Time Machine Retro-Inspired SmartwatchTime Machine Retro-Inspired Smartwatch Talos, Keeping You Safe During Your CommuteTalos, Keeping You Safe During Your Commute Bluetooth Energy Usage MonitorBluetooth Energy Usage Monitor Electric Skateboard ControllerElectric Skateboard Controller Wooden Bluetooth Remote for Lego Duplo TrainWooden Bluetooth Remote for Lego Duplo Train Ikea Eneby Speaker ControllerIkea Eneby Speaker Controller Pixl.js Wireless Weather StationPixl.js Wireless Weather Station Temperature Controlled Night Light with Puck.jsTemperature Controlled Night Light with Puck.js Infrared Record and Playback with Puck.jsInfrared Record and Playback with Puck.js Door Controlled Light with Puck.jsDoor Controlled Light with Puck.js Freezer AlarmFreezer Alarm

There are many more tutorials that may not be specifically for you device but will probably work with some tweaking. Try searching to find what you want.

Information

Certifications:

Power Consumption

Right now you can expect around 1 month of battery life with a clock that updates once a minute, using the latest firmware.

A clock that updates once a second all the time (like s7clk) will reduce the battery life to 2 weeks, and more complicated clocks can increase the power draw further.

LCD Screen

Bangle.js displays the REPL (JavaScript console) if Debug Info: show has been set in settings. If enabled, any calls like print("Hello") or console.log("World") will output to the LCD when there is no computer connected via Bluetooth. Any errors generated when there is no connection will also be displayed on the LCD.

Graphics

You can output graphics on Bangle.js's display via the global variable g that is an instance of the Graphics class. Unlike Bangle.js 1, the display is buffered so changes to the display will only take effect when you call g.flip() or your code finishes executing and Bangle.js returns to idle.

// Draw a pattern with lines
g.clear();
for (i=0;i<64;i+=7.9) g.drawLine(0,i,i,63);
g.drawString("Hello World",30,30);

Bangle.js comes with a built-in menu library that can be accessed with the E.showMenu() command.

E.showPrompt() and E.showMessage() can also be used for simple prompts and full-screen messages.

// Two variables to update
var boolean = false;
var number = 50;
// First menu
var mainmenu = {
  "" : {
    "title" : "-- Main Menu --"
  },
  "Beep" : function() { Bangle.beep(); },
  "Buzz" : function() { Bangle.buzz(); },
  "Submenu" : function() { E.showMenu(submenu); },
  "A Boolean" : {
    value : boolean,
    format : v => v?"On":"Off",
    onchange : v => { boolean=v; }
  },
  "A Number" : {
    value : number,
    min:0,max:100,step:10,
    onchange : v => { number=v; }
  },
  "Exit" : function() { E.showMenu(); },
};
// Submenu
var submenu = {
  "" : {
    "title" : "-- SubMenu --"
  },
  "One" : undefined, // do nothing
  "Two" : undefined, // do nothing
  "< Back" : function() { E.showMenu(mainmenu); },
};
// Actually display the menu
E.showMenu(mainmenu);

See http://www.espruino.com/graphical_menu for more detailed information.

Terminal

Bangle.js's LCD acts as a VT100 Terminal. To write text to the LCD regardless of connection state you can use Terminal.println("your text"). Scrolling and simple VT100 control characters will be honoured.

You can even move the JavaScript console (REPL) to the LCD while connected via Bluetooth, and use your bluetooth connection as a simple keyboard using the following commands:

Bluetooth.on("data",d=>Terminal.inject(d));
Terminal.setConsole();

Screenshots

On Bangle.js 2, there's an offscreen buffer for the display (described above). As a result it is possible to create a screenshot of what's on the display with a simple command. Just type:

g.dump()

In the left-hand side of the IDE. The contents of the screen will then be copied into the Web IDE. From there you can copy or even right-click and save to a PNG file.

On-device Peripherals

Most peripherals on the device are accessible via fields and events on the Bangle object.

Touchscreen

Bangle.js 2 has a full touchscreen.

Bangle.on('touch', function(zone,e) { ... }); will call the function with e as an object containing {x,y} every time the screen is tapped (when unlocked).

Bangle.on('drag', function(e) { ... }); will call the function with e as an object containing {x,y,dx,dy,b} whenever a finger is dragged over the screen. b is 0 when the finger is lifted or 1 when pressed.

Bangle.on('stroke', function(e) { ... }); will call the function with e as an object containing {xy:newUint8Array(x1,y1,x2,y2,...), stroke:string/undefined} whenever a finger has been dragged over the screen for more that half the screen's distance.

stroke will only be set in the stroke event if Bangle.strokes has been set up with a series of strokes to recognise. To do this, use some code as follows. The array passed to Unistroke.new needs to be a Uint8Array of XY coordinates (as you might get from xy in the stroke event).

Bangle.strokes = {
  up : Unistroke.new(new Uint8Array([57, 151, 57, 147, 58, 136, 61, 119, 65, 102, 70, 88, 74, 78, 80, 71, 86, 70, 94, 72, 107, 79, 129, 97, 140, 110, 147, 120, 152, 127, 156, 134, 158, 137])),
  cw : Unistroke.new(new Uint8Array([91, 60, 93, 60, 98, 60, 108, 60, 121, 61, 131, 64, 137, 70, 139, 81, 139, 96, 135, 111, 128, 126, 119, 136, 108, 140, 97, 141, 86, 139, 75, 134, 70, 126, 66, 115, 64, 100, 65, 88, 69, 78, 75, 71, 81, 67, 84, 63])
),
 ccw : Unistroke.new(new Uint8Array([114, 71, 112, 71, 108, 71, 102, 71, 93, 72, 82, 76, 71, 81, 62, 88, 56, 97, 53, 107, 54, 116, 59, 127, 70, 137, 86, 142, 103, 145, 115, 144, 124, 143, 131, 136, 135, 122, 131, 99, 124, 83, 115, 72])
),
 alpha : Unistroke.new(new Uint8Array([161, 55, 160, 58, 158, 62, 155, 71, 149, 81, 141, 97, 132, 114, 119, 129, 107, 140, 96, 147, 86, 151, 77, 154, 69, 153, 59, 149, 49, 143, 40, 133, 31, 117, 28, 104, 27, 90, 28, 78, 34, 71, 44, 69, 60, 72, 84, 84, 111, 107, 132, 128, 146, 144, 154, 155, 159, 161])),
 right : Unistroke.new(new Uint8Array([49, 52, 54, 52, 68, 57, 90, 65, 114, 76, 134, 84, 148, 91, 157, 95, 163, 98, 167, 100, 169, 102, 168, 105, 163, 114, 147, 126, 127, 137, 107, 147, 94, 152, 82, 156, 72, 159])),
double : Unistroke.new(new Uint8Array([75, 61, 87, 61, 117, 68, 142, 85, 147, 111, 129, 134, 92, 140, 59, 133, 45, 116, 50, 89, 86, 72, 128, 88, 138, 121, 108, 138, 68, 129, 56, 104, 57, 90]))
};

LED

There are two 'fake' LED variables called LED1 and LED2 that create red and green fake LEDs at the top of the watch screen - these serve no purpose other than to allow tutorials for existing Espruino boards to be used.

If you want to control the backlight LED use Bangle.setLCDBrightness.

Vibrate

Bangle.buzz() will make Bangle.js's vibration motor turn on. It takes optional time and strength arguments, and returns a promise. See the reference.

For example:

Bangle.buzz().then(()=>{
  return new Promise(resolve=>setTimeout(resolve,500)); // wait 500ms
}).then(()=>{
  return Bangle.buzz(1000);
}).then(()=>{
  console.log("Done");
});

Will do a short buzz followed by a long buzz and will print Done when finished.

Sound

You can use Bangle.beep() in much the same way as .buzz above to make sounds. See the reference.

To output an entire scale of notes, you could do:

Bangle.beep(200,207.65*8).then(
()=>Bangle.beep(200,220.00*8)).then(
()=>Bangle.beep(200,246.94*8)).then(
()=>Bangle.beep(200,261.63*8)).then(
()=>Bangle.beep(200,293.66*8)).then(
()=>Bangle.beep(200,329.63*8)).then(
()=>Bangle.beep(200,369.99*8)).then(
()=>Bangle.beep(200,392.00*8)).then(
()=>Bangle.beep(200,440.00*8));

Note: Bangle.js 2 does not contain a piezo speaker, but instead uses the vibration motor for sound. This means that while you can get some sound, it is extremely weak.

Buttons

There is just one button on Bangle.js - called BTN or BTN1 in code.

setWatch(function() {
  console.log("Pressed");
}, BTN, {edge:"rising", debounce:50, repeat:true});

Accelerometer

The accelerometer runs all the time and produces accel events on the Bangle object.

Bangle.on('accel', function(acc) {
  // acc = {x,y,z,diff,mag}
});

See the reference for more information.

Gestures

When a sudden movement is detected, the accelerations in it are recorded and a gesture event is created.

If .tfmodel and .tfnames files are created in storage, Tensorflow AI will be run on the model with the gesture information and an aiGesture event will be created with the name of the detected gesture.

Compass

The compass can be turned on with Bangle.setCompassPower(1) and when enabled, mag events are created 12.5 times a second:

Bangle.setCompassPower(1)
Bangle.on('mag', function(mag) {
  // mag = {x,y,z,dx,dy,dz,heading}
});

See the reference for more information.

Barometer / air pressure sensor

To use the barometer, you can either request one pressure value:

Bangle.getPressure().then(print)
// prints this after ~1 sec
// { "temperature": 23.03918464465, "pressure": 1005.56287398937, "altitude": 64.19805781010 }

Or can request to be notified on each new reading:

Bangle.setBarometerPower(true)
Bangle.on('pressure', print)
// prints...
{ "temperature": 23.14690527655, "pressure": 1005.79911673786, "altitude": 62.21919777595 }
{ "temperature": 23.14200888113, "pressure": 1005.84599901953, "altitude": 61.82653852506 }
{ "temperature": 23.14200888113, "pressure": 1005.79091150423, "altitude": 62.28792165657 }
{ "temperature": 23.14690527655, "pressure": 1005.79911673786, "altitude": 62.21919777595 }

See the reference for more information.

GPS

The GPS can be turned on with Bangle.setGPSPower(1) and when enabled, GPS events are created once a second:

Bangle.setGPSPower(1)
Bangle.on('GPS', function(gps) {
  // gps = {lat,lon,alt,speed,etc}
});

GPS-raw events are also created containing a String for each NMEA line that comes from the GPS receiver. These contain far more detailed information from the GPS.

See the reference for more information.

Advanced GPS

For more information GPS commands see the Technical Information Page

Hardware SWD

Bangle.js 2 has the hardware SWD pin brought out on the back of the watch along with the charging pins:

For more information see the Technical Information Page

Firmware Updates

App Loader

Bangle.js 2 provides its own firmware update mechanism using the App Loader.

On Bangle.js 2 this is the recommended method (although other methods still work). Simply click on the ≡ icon to the right of the Firmware Update app and follow the instructions.

The firmware will upload to Bangle.js, and when it is complete, Bangle.js will restart and install the firmware.

Note: KickStarter Bangles that shipped with 2v10 firmware will have 2v10 bootloaders which need updating before you use the firmware updater. Just follow the instructions on the Firmware Update page to update your bootloader.

DFU

Please see the Firmware Update page for detailed instructions.

Troubleshooting

Check out:

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